Why Do Homes Have a Crawl Space?

What is a crawl space and why do homes have a crawl space?

Simply put, a crawl space is similar to a basement but is vented to outside
air. Some crawl spaces can be full-height like a basement, where others
can be two feet tall or shorter, so that you have to crawl around on your belly.

So why do homes have a crawl space? The two primary reasons homes have
crawl spaces are cost and accessibility - since crawl spaces work by allowing
outside air to circulate beneath the house. By building the floor of a
home off the ground (as opposed to on a concrete slab-on-grade), there
are several benefits, including:

Cost effectiveness. Moving dirt to level a sloping lot for a concrete pad
can get expensive; a crawl space negates that need.

Convenience. You get a handy place to install the HVAC unit and piping,
as well as water and sewer distribution throughout the house. This also
makes future repairs and replacements easier.

Unfortunately, with great cost-savings and convenience comes great responsibility.
The question, "why do homes have a crawl space" can be answered
negatively. Homes built over crawl spaces have the tendency to suffer
from moisture-related issues because of the crawl space's surroundings
(what sort of landscaping is directly outside the walls of the crawl space
that is being vented inside?). Mold, wood rot, and termite infestation
are often the result of moisture problems in crawl spaces.
One great way to combat this is by utilizing a vapor barrier and dehumidifier
in the crawl space, which will greatly reduce the amount of moisture. This can drastically reduce your crawl space's risk for:

Mold/mildew

Wood rot and structural damage

Floor failure

Decreased insulation R-values

Increased heating and cooling bills

Odors

Insects

Dust mites

Allergy aggravation

Poor indoor air quality

What is a crawl space vapor barrier?

Crawl space vapor barriers prevent ground moisture evaporation from entering
your crawl space air. When you couple a crawl space vapor barrier system
with a waterproofing system, moisture and water can be barred from the
crawl space before it has a chance to cause problems - which means no
more mold, foul odors, rot, rust, insects, rodents, and other humidity-
or moisture-related problems. So why do homes have a crawl space and how
can a vapor barrier help fix its issues?

A vapor barrier itself is designed to resist the flow of air. By stopping
air movement, it turns your crawl space into a semi-conditioned area by
making the temperature close to the living spaces in your home above the
crawl space. When the temperature in your crawl space is similar to the
temperature in your home's living areas, your floors feel warmer in
the winter.

A crawl space vapor barrier system also has been known to slow the movement
of harmful gases like radon from infiltrating the soil, helping the crawl
space vapor barrier system greatly reduce the levels of radon found in the home.

Why use a dehumidifier?

As the air in your home rises, it carries with it the air that was previously
in the crawl space. That includes moisture and mold spores, as well as
anything else that may be airborne down there. As this air rises in the
home, replacement air is drawn through the vents. This replacement air
is made up of unconditioned outside air that enters through vents and
other leaks.

Because of that, whatever is in the air at the lowest point of your home
eventually flows up into the living areas. Almost half of the air we breathe
on the first floor of our home comes from the crawl space. A dirt crawl
space with open crawl space vents is a never-ending source of moisture.
Even if the dirt's surface seems dry, digging down a few inches reveals
moist earth. This moisture is constantly released into the crawl space.
So why do homes have a crawl space and how can a dehumidifier help? Using
a dehumidifier can help to reign in any moisture problems as well as provide:

Health protection.

Pest protection.

Increased structural integrity.

Living space comfort.

What are additional ways to prevent crawl space issues?

Another common issue among crawl spaces is improper grading and a lack
of rain gutters, which contributes to crawl space moisture control issues
by allowing unwanted rain or ground water to enter the crawlspace. This
repeated wetting of building materials day after day provides the perfect
environment for mold growth, termites and structural damage under your home.

In addition to crawl space vapor barriers paired with dehumidifiers, there
are several solutions you can look at when dealing with water in the crawl
space include:

Proper grading around the home directing moisture away from the structure.

Installing, repairing or cleaning gutters and downspouts.

Adding downspout extensions and exit lines to move water further from the home.